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soil mineral

Catalogue: GRDC Updates
In low rainfall areas or in drier seasons rainfall may be too low or variable to get consistent results from delayed N. Figure 3b shows that the risk associated with a delayed N strategy increases at sites were yields were less than about 2,500 kg/ha: the variation in the response to N applied at stem elongation is high and in many cases there are lower yields from delayed applications compared to N applied at sowing... Experiments over many years have shown that there is no consistent difference in the response to different forms of N fertiliser when compared at the same rate of N and the same time of application... Recent work from Victoria suggest losses of N from volatilisation of up to 1% per day with urea and about half that for UAN and ammonium sulphate (Table 1)...
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Catalogue: GRDC Updates (West)
Mention of a trade name or company in this publication does not imply endorsement of any product or company by Department of Agriculture.. Crop Updates is a partnership between the Department of Agriculture, Western Australia and the Grains Research & Development Corporation i.. Overall, Roundup was more effective than Gramoxone in killing wild radish, irrespective of herbicide rate...
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Catalogue: GRDC Updates
Irrigated wheat appears to have a similar optimum planting rate to dryland: around 40kg/ha (100 plants/m2), possibly lower if the seed is going to be concentrated on top of a bed with large furrow gaps between beds. Planting higher rates than this will increase lodging susceptibility and could cause yield loss if it induces greater rates of lodging... Further work will be needed to experiment with different timings of N application to see how sensitive the strategy is to the date of N application, and if any slow release fertiliser products would be of benefit... Yield and water use benchmarks Preliminary analysis has been undertaken to determine the maximum yields that can be achieved from irrigated wheat in the northern region, and how much water is required by the crop in order to achieve these yields...
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Catalogue: Ground Cover
The CSIRO has discovered an Australian strain of a "mineral-eating" fungus that promises to release nutrients from soil minerals and boost crop yields... The strains that have now been discovered can release nutrients from soil minerals... To date, the major limitation has been the identification and development of strains of Penicillium suited to local soils and environmental conditions...
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Catalogue: GRDC Updates
If we use the same bulk density as above (1.2 g/cm3) and restrict our calculations to the top 10 cm of soil where organic carbon is most easily increased, at 2% carbon the soil would contain 24 tonnes C/ha... In Figure 4 the estimated changes in soil organic carbon content (%) of the 0-10 cm layer that occur with different levels of wheat production (grain yield) are presented... Results indicate that a sustained productivity of about 4 tonnes/ha/year of wheat grain yield is required to maintain the equilibrium soil carbon content at Roseworthy (Figure 4 a)...
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Catalogue: GRDC Updates
The early research also showed that in dry environments the changes in total soil-N were equal to the N removed in crops, but in wetter environments there was more loss of soil N than removal of crop N, probably because of loss of soil N due to denitrification... Many of the long-term experiments discussed earlier showed that introducing pastures into the rotation stabilised the soil total N... Nitrogen balance and gross margin estimated for farms in southern NSW (Angus and Peoples (2012)...
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Catalogue: GRDC Updates
Partial P budgets (P applied minus P removed in harvested product) are generally negative across the northern grains region indicating that soil P reserves are being used to support crop growth, but the uncertainty in prediction of crop P requirements from pre-plant soil tests has been highlighted by the results obtained from numerous P rate field experiments undertaken in GRDC project DAQ00084... To assess the availability of this acid extractable P, iron oxide strips were used as 'sinks' to continuously remove P from the soil solution forcing P desorption and dissolution of P compounds to replenish soil solution P. Figure 2 indicates that the acid extractable fraction was a major contributor of P to the soil solution and is potentially available to crops... Field experiments have confirmed the unreliability of Colwell-P for discriminating P-responsive from P-adequate sites, even if the Colwell-P status of the sub-surface is considered as being more representative than the 0-10 cm layer of the soil being exploited by the crop roots...
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Catalogue: Ground Cover
Plants take carbon dioxide (CO2) from the air for growth and add it to the soil through plant debris.. Wayne Pluske, from independent WA-based soils consultancy Equii, says while carbon is essential for plant growth it does not need to be applied to the soil as a fertiliser like other nutrients such as nitrogen, phosphorus and sulfur... If there are not enough nutrients in the organic materials being decomposed, soil microorganisms will source it from elsewhere and, at least temporarily, deplete the plant-available pool of nutrients in the soil...
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Catalogue: Ground Cover
Measuring nitrogen is first step to lifting efficiency.. N is oversupplied: the amount of nitrogen applied can be greater than the crop or grain's demand, either because yield potential was overestimated, soil N mineralisation potential was not considered, or residual soil mineral N was underestimated... Available in soil but not taken up: N that is not taken up in soil can be because: mineral N is not near the active root mass for most of the crop's growth; root depth or density is restricted by chemical, physical or biological factors, such as phosphorus deficiency, compaction or root disease; or the products applied may not release N when the crop wants it...
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Catalogue: Ground Cover
N is oversupplied: the amount of nitrogen applied can be greater than the crop or grain's demand, either because yield potential was overestimated, soil N mineralisation potential was not considered, or residual soil mineral N was underestimated... N is applied but temporarily unavailable: up to 18 kilograms of N per tonne of cereal stubble can be unavailable to the crop if N is immobilised in soil... Available in soil but not taken up: N that is not taken up in soil can be because: mineral N is not near the active root mass for most of the crop's growth; root depth or density is restricted by chemical, physical or biological factors, such as phosphorus deficiency, compaction or root disease; or the products applied may not release N when the crop wants it...
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